1. Field of the Invention
The invention pertains to a device for the amplification of light-sensitive medium optic signals used to amplify a temporally modulated signal wave at high frequency. According to the invention, the amplification results from wave-coupling phenomena in light-refracting crystals. This device has a high-pass type of response which permits the amplification of high-frequency modulated signals. The applications relate to the optical processing of the signals and especially to the regeneration and amplification of signals coming from an optic fiber.
2. Description of the Prior Art
Devices for the amplification of light waves using light-sensitive elements have already been experimented with.
The French patent filed on Feb. 27th, 1981 under the number 81.03989 and published under the number 2 500 937 describes an optic device to maintain a radiant energy pulse circulating in a waveguide. This device uses a light-refracting medium, in which the signal to be maintained interferes, and a pumping wave. A transfer of energy takes place from the pumping beam towards the signal to be maintained.
The French patent filed on Mar. 13th, 1981 under the number 81.01535 and published under the number 2 501 872 also describes an optic device for the real-time amplification of the radiant energy of a beam. This amplifier uses a light-sensitive recording material in which a beam to be amplified and a reference beam interfere. These beams create a grating of indices strata in the light-sensitive medium. Energy is transferred between the reference beam and the target beam, adding energy to the target beam. To work in optimum energy transfer conditions, this amplifier provides for a displacement of the interference fringes either through a mechanical displacement of the light-sensitive recording material or through the phase modulation of one of the beams.
However, prior art system cannot be used to amplify pulse trains that occur at high frequencies, such as the pulse trains transmitted in optical telecommunications. For the inertia of light-sensitive media does not permit the amplification of these pulse trains.
The device of the invention, by contrast, takes advantage of this inertia to enable the amplification of pulses occurring at high frequencies.